1/2 inch instead of 3/8 should give you about 8 more inches in height that you can go. Maybe adding a 1/2 inch to the border in the front will help. Hope you have along arm,
. The bottom is going to be a long ways away when full. I can not figure out why plywood would stop at 24 inches unless it is weaker than glass. Maybe a plywood that has 12 or more layers and is 7/8 or 1 inch would be a safer bet, and a good cabinet grade.
All in all, I think the tank will be fun and if it works, it would be an awesome one to establish some really cool planted areas, fish establishing territories and all in all a tank that will keep you very busy.